Does a neural residual help a quadrotor attitude controller once roll, pitch and yaw are coupled?
research/codesign-aero-coupled
Does a residual network or analytic gyroscopic compensation beat per-axis PID on a coupled three-axis quadrotor? No: the residual is worse than PID in 26 of 30 pairs (+0.32° held out) and compensation changes the error by 0.001°; yaw authority sets the error.
What it found
Follow-up to codesign-aero-skip: roll, pitch and yaw with Euler gyroscopic coupling and a weak yaw axis. On six airframes × five CMA-ES seeds, held-out combined RMS attitude error is 17.76° for a 576-evaluation per-axis PID, 18.08° for PID plus an 83-parameter zero-initialised residual network (PID better in 26 of 30 pairs), and 18.20° for the 96-evaluation PID with or without analytic gyroscopic compensation (difference −0.001°). A 12-condition sweep over Iz/Ix (1.0–3.0), manoeuvre size and yaw authority finds the PID ahead of the residual in all 12 and compensation worth at most 0.016°, even where the gyroscopic term peaks at 71% of the torque limit. Yaw (about 29° RMS on 30° steps) is authority-limited and dominates the error; tripling yaw authority helps by 1.8°, the control-law class does not. Limits: the yaw reaction-torque ratio, inertia ratio and plant ranges are assumed and swept, not measured; attitude only with step references; the residual overfits 16 training episodes and a different learner might differ.
A figure from its own output

Paper, code and results
More in Agentic co-design of low-cost robots
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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.